The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 11, 1994
Filed:
May. 19, 1993
Donald F Johann, Palo Alto, CA (US);
John E DeFiore, Sunnyvale, CA (US);
Maxoptix Corporation, San Jose, CA (US);
Abstract
An optical recording system having a DC restored read signal for qualifying pulses in the read channel. The equalized and filtered read signal is input to a differentiator and a DC restore circuit. The zero crossings of the differentiated signal which represent the peaks of the pulses are detected. The DC restore circuit inverts the read signal, generates a reference voltage, and compares the negative pulses peaks of the read signal to the reference voltage. The charge of a capacitor is adjusted according to the difference in voltages of the pulse peaks to that of the reference voltage in order to maintain a constant DC level. The DC restored signal is qualified according to a threshold. Only those pulses which have zero crossings and which have been qualified are considered to be valid.